HESrEROEXlTUlD.E. 205 



vomers, instead of the (lcei)ly cleft single vomer of the latter ; 

 appaieiitly no basiptorygoitl processes ; angle of maudible prolonged 

 backwards. 



The tarso-metatarsus is of moderate length, laterally compressed, 

 grooved anteriorly, without talon, and the distal trochlea; gradually 

 diminishing in size and length from the fourth to the second, the 

 latter being reflected. The tibio-tarsus (fig. 49, B) approximating to 

 that of Cuh/mbus, but with tho spike-like patella (fig. 49, C) not 

 anchylosed to the cncmial crest, and perforated by a foramen for the 

 tendon of tho ambiens muscle ; no extensor bridge. The femur 

 (fig. 49, ¥,) is short and expanded laterally and compressed from back 

 to front to a greater degree than in Coh/mhus (fig. 49, D). The 

 pelvis (fig. 50) is of the elongated type found in Coh/mhus, but the 

 shaft of the ischium is entirely free from the ilium. The cervical 

 vertebra; (especially those in the anterior part of the series) closely 

 resemble those of Cohjnihus. 



The writer's study of the skeleton leads him to endorse the conclu- 

 sions arrived at by D'Arcy Thompson ' as to the close affinity of 

 Hesi^eroniis with Coli/mhus, and its total distinctness from the llatita;, 

 the apparent resemblances in the pectoral girdle and sternum to 

 the latter being apparently due to the loss of the power of flight. 

 The arguments in favour of this view being fully detailed in the 

 memoir cited, need not be recapitulated. 



Genus HESPERORNIS, Marsh \ 

 Syn. Lcstornis, Marsh ■*. 

 The type and only described genus. 



Hesperornis regalis, Marsh \ 



The type species. In a standing position about one metre in 

 height. 



Hab. North America. 



The originals of the undermtntioned sjKcimens, which are preserved 

 in the Museum of Yah CoUaje, Philadelphia, tvere obtained from 

 the Cretaceous of Kansas. The casts were presented by Prof. 

 0. C. Marsh. 



A. 19. Cast of a portion of the left ramus of the mandible, showing 

 three teeth. 



' Stud. Mus. Uumlee, vol. i. art x. (1890). 



'■' Amer. Joun:. ser. o, vul. iii. p. o7 (187l')' ^ -^^«/. vol. xi. p. JO'J (1876). 



* Ibid. vol. iii. p. o7 (1872). 



